docs: def set_summary_data(self, group_name, section_name, data):
          """ Set the summary data for an analysis group.
  
          :param group_name: The name of the analysis group.
          :param section_name: The analysis step. This will become a
              subfolder in the Summary section.
          :param data: A dictionary containing keys which are the summary
              fields, and values which are the summary values.
          """
          self.assert_writeable()
          group = 'Analyses/{}/Summary/{}'.format(group_name, section_name)
          self._add_group(group, data)